title: Cerebellar motor learning deficits in medicated and medication-free men with recent-onset schizophrenia.
abstract: BACKGROUND
  The notion that cerebellar deficits may underlie clinical symptoms in people with schizophrenia is tested by evaluating 2 forms of cerebellar learning in patients with recent-onset schizophrenia. A potential medication effect is evaluated by including patients with or without antipsychotics.
  
  
  METHODS
  We assessed saccadic eye movement adaptation and eyeblink conditioning in men with recent-onset schizophrenia who were taking antipsychotic medication or who were antipsychotic-free and in age-matched controls.
  
  
  RESULTS
  We included 39 men with schizophrenia (10 who were taking clozapine, 16 who were taking haloperidol and 13 who were antipsychotic-free) and 29 controls in our study. All participants showed significant saccadic adaptation. Adaptation strength did not differ between healthy controls and men with schizophrenia. The speed of saccade adaptation, however, was significantly lower in men with schizophrenia. They showed a significantly lower increase in the number of conditioned eyeblink responses. Over all experiments, no consistent effects of medication were observed. These outcomes did not correlate with age, years of education, psychopathology or dose of antipsychotics.
  
  
  CONCLUSIONS
  As patients were not randomized for treatment, an influence of confounding variables associated with medication status cannot be excluded. Individual patients also varied along the schizophrenia spectrum despite the relative homogeneity with respect to onset of illness and short usage of medication. Finally, the relatively small number of participants may have concealed effects as a result of insufficient statistical power.
  
  
  CONCLUSIONS
  We found several cerebellar learning deficits in men with schizophrenia that we cannot attribute to the use of antipsychotics. Although this finding, combined with the fact that deficits are already present in patients with recent-onset schizophrenia, could suggest that cerebellar impairments are a trait deficit in people with schizophrenia. This should be confirmed in longitudinal studies.
authors.affiliation: The Departments of Psychiatry and Neuroscience, Erasmus MC, Rotterdam, and the Delta Psychiatric Centre, Poortugaal, the Netherlands.
authors.forename: Michael
authors.initials: M
authors.lastname: Coesmans
authors.affiliation: Department of Psychiatry, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Christian H
authors.initials: CH
authors.lastname: Röder
authors.affiliation: The Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Albertine E
authors.initials: AE
authors.lastname: Smit
authors.affiliation: The Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Sebastiaan K E
authors.initials: SK
authors.lastname: Koekkoek
authors.affiliation: The Department of Neuroscience, Erasmus MC, Rotterdam, and The Netherlands Institute for Neuroscience, Royal Dutch Academy of Arts & Sciences, Amsterdam, the Netherlands.
authors.forename: Chris I
authors.initials: CI
authors.lastname: De Zeeuw
authors.affiliation: The Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Maarten A
authors.initials: MA
authors.lastname: Frens
authors.affiliation: The Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Josef N
authors.initials: JN
authors.lastname: van der Geest
mesh_terms: D000223:Adaptation, Psychological / Q000187:drug effects / Q000502:physiology; D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001767:Blinking / Q000187:drug effects / Q000502:physiology; D002531:Cerebellum / Q000187:drug effects* / Q000503:physiopathology*; D003024:Clozapine / Q000627:therapeutic use; D003215:Conditioning, Eyelid / Q000187:drug effects / Q000502:physiology; D006220:Haloperidol / Q000627:therapeutic use; D006801:Humans; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D012438:Saccades / Q000187:drug effects / Q000502:physiology; D012559:Schizophrenia / Q000188:drug therapy* / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013997:Time Factors; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine; D006220:Haloperidol